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Home >> Subaru >> 2020 >> Crosstrek Base, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 14 (P-HEV Drive Motor System (Diagnostics)) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P3124-1F: Lost Communication Between Drive Motor "A" And HV Ecu Circuit Intermittent >> Notes

DTC P3124-1F: Lost Communication Between Drive Motor "A" And HV Ecu Circuit Intermittent: Notes

WARNING: This page is about a different variant/trim than selected.

1. - 

Detecting condition: 

When DTC P0C7917, P0D3319, P1C5D19 or P1C5F19 error judgment occurs and lost communication between Motor generator control ECU and Hybrid vehicle control ECU assembly are detected

(1 trip detection logic)

Trouble symptom: 

-

Wiring diagram: 

Hybrid system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>HYBRID ELECTRIC VEHICLE SYSTEM>WIRING DIAGRAM .

G13618143Courtesy of SUBARU OF AMERICA, INC.
CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .
G13615891Courtesy of SUBARU OF AMERICA, INC.
G13615892Courtesy of SUBARU OF AMERICA, INC.
  1. CHECK DTC  .
    1. Using the Subaru Select Monitor, perform the clear memory of [P-HEV Drive Motor]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
    2. Using the Subaru Select Monitor, read [Diagnosis Related Information] of [P-HEV Drive Motor]. Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>WORK SUPPORT .
    3. Read the DTC of [P-HEV Drive Motor] using the Subaru Select Monitor. Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

    Is diagnostic related information, DTC P31241F or P312487 displayed?

    Yes:  Go to  2.

    No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

    NOTE: In this case, temporary poor contact of connector, or temporary open or short circuit of the Wire harness may be the cause.
  2. CHECK Hybrid vehicle control ECU assembly (WAVEFORM CHECK)  .

    Connect an oscilloscope to Hybrid vehicle control ECU assembly terminal and measure the waveform.

    Measured terminal 

    CH2: (B606) No. 20 (HMCL) ←→ (i369) No. 6 (E1)

    CH1: (B606) No. 28 (HMCH) ←→ (i369) No. 6 (E1)

    Gauge set: 1 V/DIV, 200 μs./DIV

    Condition: IG ON

    NOTE:
    • Check with the connector connected.
    • Waveform is normal if a pulse generates.
    • Waveform pulse changes depending on communication conditions.
    G13615893Courtesy of SUBARU OF AMERICA, INC.

    Is the waveform shown in the figure measured at IG ON?

    Yes:  Replace Inverter with converter assembly. Ref. to HYBRID ELECTRIC VEHICLE>INVERTER AND CONVERTER ASSEMBLY .

    No:  Go to  3.

  3. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter with converter assembly) (SHORT TO POWER SUPPLY)  .
    CAUTION: Make sure to wear insulated gloves and protective goggles during the work.
    1. Check that the Service plug is disconnected. Ref. to HYBRID ELECTRIC VEHICLE>SERVICE PLUG .
    2. Disconnect Inverter with converter assembly connector (HV23).
    3. Disconnect Hybrid vehicle control ECU assembly connector (B606).
    4. Connect the Battery (12V) ground terminal. Ref. to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
    5. Turn to IG ON.
    6. Using a tester, measure the voltage between Hybrid vehicle control ECU assembly connector and chassis ground.

    Connector & terminal 

    (B606) No. 28 (+) - Chassis ground (-):

    (B606) No. 20 (+) - Chassis ground (-):

    Is the voltage less than 1 V?

    Yes:  Go to  4.

    No:  Repair or replace the Wire harness or the connector.

  4. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter with converter assembly) (OPEN CIRCUIT)  .
    CAUTION: Make sure to wear insulated gloves and protective goggles during the work.
    1. Turn the ignition to OFF.
    2. Disconnect the ground terminal of Battery (12V). Ref. to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
    3. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector and Inverter with converter assembly connector.

    Connector & terminal 

    (HV23) No. 20 - (B606) No. 28:

    (HV23) No. 24 - (B606) No. 20:

    Is the resistance less than 1 Ω?

    Yes:  Go to  5.

    No:  Repair or replace the Wire harness or the connector.

  5. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter with converter assembly) (SHORT TO GROUND OR LINE-TO-LINE SHORT)  .
    CAUTION: Make sure to wear insulated gloves and protective goggles during the work.

    Using a tester, measure the resistance between terminals in Hybrid vehicle control ECU assembly connector, and between Hybrid vehicle control ECU assembly connector and chassis ground.

    Connector & terminal 

    (B606) No. 28 - (B606) No. 1 - 35:

    (B606) No. 28 - Chassis ground:

    (B606) No. 20 - (B606) No. 1 - 35:

    (B606) No. 20 - Chassis ground:

    Is the resistance 10 kΩ or more?

    Yes:  Go to  6.

    No:  Repair or replace the Wire harness or the connector.

  6. CHECK Inverter with converter assembly  .
    1. Connect the connector (HV23) of Inverter with converter assembly.
    2. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector terminals.

    Connector & terminal 

    (B606) No. 28 - (B606) No. 20:

    Is the resistance 80 - 170 Ω?

    Yes:  Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

    No:  Replace Inverter with converter assembly. Ref. to HYBRID ELECTRIC VEHICLE>INVERTER AND CONVERTER ASSEMBLY .

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